// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef IPC_ATTACHMENT_BROKER_UNPRIVILEGED_H_
#define IPC_ATTACHMENT_BROKER_UNPRIVILEGED_H_

#include "base/macros.h"
#include "base/memory/scoped_ptr.h"
#include "ipc/attachment_broker.h"
#include "ipc/ipc_export.h"

namespace IPC {

class Endpoint;
class Sender;

// This abstract subclass of AttachmentBroker is intended for use in
// non-privileged processes.
class IPC_EXPORT AttachmentBrokerUnprivileged : public IPC::AttachmentBroker {
public:
    AttachmentBrokerUnprivileged();
    ~AttachmentBrokerUnprivileged() override;

    // If there is no global attachment broker, makes a new
    // AttachmentBrokerUnprivileged and sets it as the global attachment broker.
    // This method is thread safe.
    static void CreateBrokerIfNeeded();

    // AttachmentBroker:
    void RegisterBrokerCommunicationChannel(Endpoint* endpoint) override;
    void DeregisterBrokerCommunicationChannel(Endpoint* endpoint) override;
    bool IsPrivilegedBroker() override;

protected:
    IPC::Sender* get_sender() { return sender_; }

    // Errors that can be reported by subclasses.
    // These match tools/metrics/histograms/histograms.xml.
    // This enum is append-only.
    enum UMAError {
        // The brokerable attachment was successfully processed.
        SUCCESS = 0,
        // The brokerable attachment's destination was not the process that received
        // the attachment.
        WRONG_DESTINATION = 1,
        // An error occurred while trying to receive a Mach port with mach_msg().
        ERR_RECEIVE_MACH_MESSAGE = 2,
        ERROR_MAX
    };

    // Emits an UMA metric.
    void LogError(UMAError error);

private:
    // |sender_| is used to send Messages to the privileged broker process.
    // |sender_| must live at least as long as this instance.
    IPC::Sender* sender_;
    DISALLOW_COPY_AND_ASSIGN(AttachmentBrokerUnprivileged);
};

} // namespace IPC

#endif // IPC_ATTACHMENT_BROKER_UNPRIVILEGED_H_
